Merge pull request cryptonomex#629 from bitshares/180202-fix-windows-…

…build

Fix Windows build

libraries/app/util.cpp

@@ -54,7 +54,7 @@ fc::uint128 to_capped128( const u256& t )
 string uint128_amount_to_string( const fc::uint128& amount, const uint8_t precision )
 { try {
    string s = string( amount );
-   if( precision == 0 || amount == 0 )
+   if( precision == 0 || amount == fc::uint128() )
       return s;
 
    std::stringstream ss;